xo-expression2/xo-reader/include/xo/reader/expect_expr_xs.hpp
Roland Conybeare 0ae98c211d Add 'xo-reader/' from commit 'c46c0f1cc4'
git-subtree-dir: xo-reader
git-subtree-mainline: dacdeb2cd7
git-subtree-split: c46c0f1cc4
2025-05-11 01:40:20 -05:00

77 lines
2.8 KiB
C++

/* file expect_expr_xs.hpp
*
* author: Roland Conybeare, Aug 2024
*/
#pragma once
#include "exprstate.hpp"
namespace xo {
namespace scm {
/** @class expect_expr_xs
* @brief state machine to expect + capture an expression
**/
class expect_expr_xs : public exprstate {
public:
explicit expect_expr_xs(bool allow_defs,
bool cxl_on_rightbrace);
static void start(parserstatemachine * p_psm);
static void start(bool allow_defs,
bool cxl_on_rightbrace,
parserstatemachine * p_psm);
virtual void on_lambda_token(const token_type & tk,
parserstatemachine * p_psm) override;
virtual void on_def_token(const token_type & tk,
parserstatemachine * p_psm) override;
virtual void on_leftparen_token(const token_type & tk,
parserstatemachine * p_psm) override;
virtual void on_leftbrace_token(const token_type & tk,
parserstatemachine * p_psm) override;
virtual void on_rightbrace_token(const token_type & tk,
parserstatemachine * p_psm) override;
virtual void on_symbol_token(const token_type & tk,
parserstatemachine * p_psm) override;
virtual void on_f64_token(const token_type & tk,
parserstatemachine * p_psm) override;
/** update exprstate in response to a successfully-parsed subexpression **/
virtual void on_expr(ref::brw<Expression> expr,
parserstatemachine * p_psm) override;
/** update exprstate in response to a successfully-parsed subexpression,
* that's terminated by semicolon ';'
**/
virtual void on_expr_with_semicolon(ref::brw<Expression> expr,
parserstatemachine * p_psm) override;
private:
static std::unique_ptr<expect_expr_xs> make(bool allow_defs,
bool cxl_on_rightbrace);
private:
/* if true: allow a define-expression here */
bool allow_defs_ = false;
/* if true: expecting either:
* - expression
* - right brace '}', in which case no expression
* if false: expecting
* - expression
*/
bool cxl_on_rightbrace_ = false;
};
} /*namespace scm*/
} /*namespace xo*/
/* end expect_expr_xs.hpp */